Chain cutter for sewing machines



-April 21, 1931.

Filed Nov. 1, 1923 3 Sheets-Sheet l I April 1931- "F. Lu rz 1,802,212

CHAIN CUTTER FOR SEWING MACHINES Filed Nov. 1, 1928 3 Sheets-Sheet 2 April 21, 1931. F. LUTZ 1,802,212

CHAIN CUTTER FOR SEWING MACHINES Filed Nov. 1. 1928 5 Sheets-Sheet 5 a i il cutting stitched articles.

Patented Apr. 21, 1931 inn'rnu srarss PATENTiOFFICE FRIEDRICH LUTZ, or s'rorrsnnr, GERMANY, .ASSIGNOR r0 UNION SPECIAL MAsoIIInnNrnBnIIr, e. M. B. 13., or STUTTGART, GERMANY 'cIrAriI CUTTER roe SEWING MACHINES Application filed November 1,1928, Serial No. 316,434, and in Germany February 6, 1928.

The invention relates to new and useful improvements in chain cutters for sewing machines, a'nd more particularly to a chain cutter which is operated automatically for the enchained thread loops between An object'of the invention is to provide a chain cutting mechanism wherein the severing devices are'power operated for severing the chain and wherein means is provided so that said power mechanism is connected to the severing devices only when there is no fabric passing through the machine and the enchained thread loops are positioned for severing. I

A further object of the invention is to provide a chain severing mechanism of the above type wherein the power operated mechanism for the chain severing devices includes clutch members which are connected for operating the chain severing devices when the presser foot is lowered by the stitched article passing from beneath the presser footand which are disconnected whena new article to be stitched passes beneath the presser foot and raises the same.

Astill further object of the invention is to provide achain cutting device of the above character wherein the cutting device when 1 disconnected from its actuating mechanism is raised from the path of travel of the fabric being stitched.

' These and other objects will in part be obvious and will in part be hereinafter more fully disclosed.

In the drawings which show by way of illustration one embodiment of the inventionf v Fig. 1 is a view from the front of the machine showing in outline'the sewing head andneedle, and showing in heavy lines the chain-severing mechanism.

Fig. 2 is a view showing more 'or less'diagrammatically a sewing machine with the chain cutter applied thereto as viewed from the end of the overhanging arm.

Fig. 3 is a sectional iew through the overhanging arm and showing the chain severingmechanism in plan view.

Fig. 4 is a view showing the chain sever- 'rear of the-presser foot for severing'the enchained thread loops between stitched articles. The movable thread severing device is mounted onthe presser bar so that said movable device-moves bodily up and down witlrthepresser foot. -Mounted on the overhanging arm is a power driven de vice which is constantly in operation when the machine is in operation. This device carries a clutch member which is normally disengaged from a cooperating clutch mem ber attached to the movable cutting blade supporting device. This is when the machine is being operated to stitch articles and an article is beneath the presser foot and the presser foot raiseda distance depending upon the thickness of the material being stitched. When the article passes from beneath the presser foot the presser foot will,

ofcourse, move downward so as to make contactwith the work support. This downin the'overhanging arm 40f the sewing machine. The needle 5 is carried by a needle bar-'6 which is reciprocated by means of a needle lever "7 mounted on a cross shaft ,8, in

ward. movement of the presser foot causes ice turn mounted in suitable supporting bearings in the overhanging arm. These parts are all of the usual construction and have been shown only diagrammatically in the drawings.

On the end of the cross shaft 8 there is a crank 9 carrying a ball stud to which a link 10 is connected. This link 10, as shown in Fig. 1, is connected at 11 to an arm 12 projecting upwardly from a hub 13. The hub 13 is mounted on a supporting bearing 14 so that the hub is free to oscillate thereon. Also carried by the hub 13 is a depending arm 15. This depending arm 15 is provided with a clutch shoulder 16. This depending member 15 is constantly oscillating when the machine is in operation.

The material is fed beneath the presser foot by means of a feed dog 17 which is of the usual four-motiontype. Mounted on a bracket 18 is a stationary cutting blade 19. Said cutting blade is secured to the bracket 18 by suitable screws 20. The upper edge of this cutting blade 19 is substantially in line with the plane of the upper face of the work support which is clearly shown in the drawings. Mounted on the presser bar 3 is a collar 21. Mounted in this collar 21 is a supporting rod 22. Said rod is secured to the collar by means of a set screw 23. Mounted on said rod 22 is a sleeve 24: provided with an upwardly projecting arm 25 and also with a laterally projecting arm 26 to which the movable cutting blade 27 is adustably clamped. A spring 28 surrounding the rod 22 has one end thereof in hooked engagement with the arm 25 and the other end thereof in hooked engagement with a bracket on the rod 22. This spring normally tends to turn the sleeve 24 in a clockwise direction thus moving the arm 25 against a stop 29. At the upper end of the arm 25 is a latch arm 30which is pivotally supported on a stud 31 carried by the arm 25. This latch arm is provided with a knife edge clutch member 32. A spring 33 bearing on the latch arm normally tends to turn the same in a downward direction. This latch arm 30 bears on the upper end of a post 34 which is mounted in a sleeve 35 carried by the bracket at the outer end of the rod 22.

A screw 36 clamps the post 34; in various adjusted positions. The depending arm 15 has its free end forked and the latch arm can swing downwardly into the recess between the forked ends of the arm 15. As clearly shown in 3 of the drawings, the knife edge clutch device 32 extends so as to overlie the forked members at the end of the 'arm 15. When the presser bar is raised by the thickness of the material passing beneath the presser foot during the stitching of an article, the rod 22 will be raised so as to lift the movable cutting blade away from the stationary cutting rsoaziz blade. The spring 28 also moves the arm 25 into engagement with the stop 29. This further tends to lift the movable cutting blade so that the lower edge of the movable cutting blade is above the plane of the lower face of the presser foot. When the material passes from beneath the presser foot at the finishing of the stitching of an article, the presser foot will move down onto the work support. This downward movement of the presser foot will lower the supporting device for the movable cutting blade so as to cause the knife edge clutch member 32 on the latch arm 30 to lie in the path of movement of the shoulder 16 of the oscillating member 15. The oscillating member 15 will engage said knife edge and move the arm 25 away from the stop 29. This will oscillate the support ing sleeve 24: in a counterclockwise direction, as viewed in Figs. 1 and 4, and will cause the movable cutting blade to engage the enchained thread loops lying over the stationary cutting blade and sever the same. This shoulder 16 on the depending member 15 which is continuously oscillating and the knife edge 32 are clutch devices which are brought into engagement when the presser foot drops to connect the movable cutting blade to a power actuated mechanism whereby said blade will be actuated for severing the enchained thread loops. The clutch devices will be disconnected from each other when the presser foot is raised by the next article to be stitched being passed beneath the front end of the presser foot. This raising of the presser foot will raise the support for the movable cutting blade and also the post 34, and this will lift the latch arm 30 so that the knife edge clutch member 32 carried thereby will be disengaged from the shoulder clutch member 16 carried by the depending arm 15. lVhen these clutch devices are disconnected then the spring 28 will at once shift the arm 25 into engagement with the stop 29, thus raising the movable cutting blade to its extreme upper position.

It will be apparent from the above description that a chain cutting device has been provided which is operated by a power mechanism and wherein said chain cutting device is clutched to and disconnected from the power actuating mechanism by the rising and falling of the presser foot so that the clutching of the movable member of the severing device to the power actuating mechanism is brought about automatically by the passing of the article which has been stitched from beneath the presser foot. It is also automatically disconnected from the power actuating mechanism when the presser foot is raised by the next article passing'beneath said foot. hen themovable blade is disconnected from its power actuating mechanism, it is alsoautomaticles, a, Z), 0, and d are shown, which are passing through a sewing machine in the direction of the arrow. The severing device is indicated at e and the line of stitching at s.

It will be noted that the enchained thread loops between the articles 0 and d have been severed and the enchained thread loops between the articles 0 and b are positioned relativeto the severing device e'so that they may be severed. The article I) is just'moving into the machine and will raise the presser foot so as to automatically throw the severing device out of action. The artiole a has not yet been fed to the machine.

It is obvious that minor changes in the details of construction andthe arrangement of the parts may be made without departing from the spirit of the invention as set forth in the appended claims.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In a sewing machine a presser foot, a chain cutter for cutting enchained thread loops between stitched articles located at the rear of the presser foot and including a movable cutting blade mounted for bodily movement with the presser foot and also independently thereof, a power actuated 'de-Y vice, and means whereby said movable blade is connected to said power actuated device when the presser foot is lowered onto the enchained thread loops and is disconnected from the actuating mechanism when the presser foot is raised by the fabricpassing beneath the same. a I

2. In a sewing machine a presser' foot,

raised by the material passing beneath the same.

3. In a sewing machine a presser foot, a work'support, a stationary chain cutter caiw ried by the work support, a rock lever mounted for bodily movement with the presser foot and for oscillating movement independently r thereof, a movable cutting blade carried by the rock lever cooperating with the stationary cutting blade, an actuating lever having a clutch shoulder, means for oscillating continuously said actuating lever, a latch arm carried by said rock lever and having a clutch member adapted to be connected to the clutch shoulder, means whereby said clutch member is caused to the same, and yielding devices for holding the movable blade in raised position when the presser foot is raised by the material.

l. In a sewing machine apresser foot, a chain cutter for cutting enchained thread loops between stitched articles located at the rear of the presser foot and including a movable cutting'blade, power means for: actuating said chain cutter, and automatic means controlled by the position of the presser foot for connecting said movable blade to the power actuating means when the presser foot is lowered onto the enchained thread loops and for disconnecting said movable cutting blade from said power means when said presser foot is raised by the material passing beneath thesame.

In testimony whereof, I aflix my signature/ FRIEDRICH LUTZ.

a work support, a stationary chain cutter carried by the work support, a rocklever mounted for bodily movement with the presser foot and for oscillating movement independently thereof, a movable cutting blade carried by the rock lever cooperating with the stationary cutting blade, an actuating lever having a clutch shoulder, means for oscillating continuously said actuating lever, alatch arm carried by said rock lever and having a clutch member adapted to be connected to the clutch shoulder, and means whereby said clutch member is caused to engage the clutch shoulder for actuating the cutting blade when the presser foot is lowered onto the enchained thread loops and for disconnecting said clutch member from said clutch shoulder when said presser foot is engage the clutch shoulder for actuating the r 

